1. Field of the Invention
The present invention relates to an occupancy sensor, and more particularly to an occupancy sensor with multi-position rotary switch that allows installer to easily, accurately set operation condition of the sensor, such as delay time, ambient light and/or dim level.
2. Description of the Prior Arts
An occupancy sensor can be used to control lighting or heater, ventilation and air conditioner (HVAC) and installed at gateway, staircase, garage, conference room, class room, warehouse or any other place wherever applicable. When an occupancy sensor detects infrared energy emitted by a human body entering its field of view, the sensor will switch on the light or HVAC and keep it on or operating as long as it continues to detect the activities of human body within its field of view. The sensor will switch off the light or HVAC if it does not detect any human activity within a period of pre-set delay time. Thus, the occupancy sensors are commonly used for energy saving by means of shutting off the unneeded lighting or HVAC operation.
The conventional occupancy sensor normally comprises a body including a human movement sensing component, a signal processing circuitry, a power switching device, such as relay or triac, and at least one potentiometer to set the operation condition of sensor, such as delay timer, ambient light level, etc. The potentiometer is normally configured on the body and can be adjusted by user or installer according to the desired operation condition. Take lighting control as an example, common adjustments including delay time which determines the time that light to be switched off after the last motion detected, and the ambient light level which prevents lighting to be switched on during daytime.
To properly set the operation condition of conventional occupancy sensor using the potentiometer has always been a very time consuming and uncertain work for installers due to high tolerance (20-30%) of potentiometer. Therefore, installer will have to spend considerable amount of time in the adjustment and verification cycle. Consider the sensors are normally installed on the ceiling or wall, numerous stair climbing ups and downs is also a physical challenge and risk of fall to installer.
To overcome the shortcomings, the present invention provides an occupancy sensor with multi-position rotary switch to obviate the aforementioned problems.